C 130 item

[GLMFAA1]

I'm new here and found an interesting item at the air show. I always wondered why when you see a C 130 parked the Blades all are in a + position and not an X or random --x-+-O-x-x--, Well there is a propeller lock that locks at the + so that is why you see this --++-O-++--

greg

[Parabat]

Good knowledge, I thought it was just the crew being tidy!

[pigsty]

I don't doubt it for a moment. But how come the P-3, with basically the same engines and propellers, is more often parked --xx-O-xx-- ?

(I know they're installed upside down compared with the C-130. That doesn't explain it!)

Edited May 20, 2014 by pigsty

[Parabat]

Maybe it's because they're lower, closer to the ground when at '+' than at at 'x', so it avoids accidental damage or stops situationally unaware people from injuring themselves!

[GLMFAA1]

I specifically asked the question to crew chief and that was the answer I got, Guess you'll have to go ask a P 3 crew chief

[pminer]

I don't doubt it for a moment. But how come the P-3, with basically the same engines and propellers, is more often parked --xx-O-xx-- ?

(I know they're installed upside down compared with the C-130. That doesn't explain it!)

One is Air Force....the other is Navy. There's s story to each though. The Air Force stows their C-130 props in the + position if the plane is not going to fly or is I.E....statically stowed for an Air Show. When the A/C is going to fly during the day or within a certain amount of time....the props go into the x position.

Same with the P-3 although the prop positions are reversed depending on whether the A/C is about to fly that day or not.

[Scooby]

I maintained the Hercules for 7 years and that is not the reason we dress the props. The #1 blade is dressed in the vertical position as that seats a piston within the prop assembly which prevents any oil from leaking from the propellor housing.

The component that could leak if the #1 blade is not vertical is called the pitch lock regulator.

On quick turns we didn't bother dressing the blades.

I am not referring to the new J models.

Edited May 21, 2014 by Scooby

[ikar]

At Littlerock the most common thing was to have the aircraft props "Xed". HTis was partly for safety, so it was a bit harder for a tug driver to hit the props. Some would "T" them which made ti easier to move maintennance stands around. Most of the 130s I saw had the props "Xed".

Of course, some people had to do both:

[GLMFAA1]

Oh boy, Did I put a stick in a hornet's nest. I was thinking that could be a point in IPMS judging.

So much for the fire guy trying to earn his wings, I'll just go drag some hose.

Hey Happy EMS week to all

greg

[DonSS3]

When I as in P-3s, we parked ours ++0++. No prop brakes or anything like that.

[DonSS3]

If you go by IPMS contest rules, that sort of thing shouldn't be considered anyway.

[ikar]

But you know now some of those gguys can be. Sometimes they think they are the absolute authority on every detail.

[GLMFAA1]

Just thought it was interesting, This was also on display so you figure it out

The props on a hurricane hunter c 130

greg

[Modeler7]

I have to disagree with an earlier post. The reason #1 blade is up is because of what is called the Beta Feedback shaft. It will leak prop fluid if it is in any other position. The Beta Feedback shaft tells the valve housing what angle the prop is at. (That is a VERY simplified way to explain it.) The pitchlock regulator is something that keeps a set of splines from engaging while pressure is on the dome assembly. The splines engaged will prevent the blade angle from decreasing to a flat or reverse position but will allow it to increase to a feather position if needed up to 92.5* blade angle to maintain a positive lock on the spline teeth.

If the prop looses pressure, the pitchlock regulator will dump pressure and the two spline gears will engage to keep the prop from doing what it wants. It will also pitchlock at 103.5% if the fuel control doesn't keep the engine below 103%. I flew 12 different C-130's in my 19 years of flying during my 24 years of Air Force service. Now, the 3-bladed props are electric and completely different than the Ham-Stan props and the J model props are completely different again. Can't compare those at all.

And here is a schematic of the pitch lock regulator.

I can get many more photos and graphics if anyone wants them but it really doesn't have much to do with model building other than the T-56 engine series -6 to -16 had the prop #1 blade at the 12 o'clock position. Right before engine start, the crew chief would break the prop break by X'ing the props. This helps the starter. The prop brake engages when prop oil pressure is above 23 psi. If the prop loses pressure, the prop brake engages and is held in place by a slight pressure on the blade to counter rotate due to blade shape. During Functional Check Flights, the prop would turn backwards all the time. We would slow down first. Then do the prop fails to feather checklist. If that didn't work, then bump a little blade angle on it to stop the spin. I could go on and on.....

MSgt (Ret.) Kelly Jamison

Former C-130 Evaluator/Instructor

317th Airlift Group, Dyess AFB, TX

[DonSS3]

Flew on P-3s (T56-10/-14 IIRC) and while we dressed the props we were never instructed which blade to have at the 12 o'clock position. Odd, maybe P-3s and C-130s had different pitch lock mechanisms? Whoever designed the stuff hat went inside that prop dome was a genius!

I think we have a couple P-3 FEs on here, maybe they'll chime in.

Edited May 27, 2014 by DonSS3

[Scooby]

I have to disagree with an earlier post. The reason #1 blade is up is because of what is called the Beta Feedback shaft. It will leak prop fluid if it is in any other position. The Beta Feedback shaft tells the valve housing what angle the prop is at. (That is a VERY simplified way to explain it.)

MSgt (Ret.) Kelly Jamison

Former C-130 Evaluator/Instructor

317th Airlift Group, Dyess AFB, TX

I was wrong in my terminology but not my explanation, the #1 blade was up to prevent prop fluid from leaking from the housing.

You are correct, it is the beta feedback shaft. It's been 20 years since I worked Hercs, since then I have worked six different airframes (1 transport, four helo types, and 1 fighter).

I loved the Herc the most though.

[Scooby]

Flew on P-3s (T56-10/-14 IIRC) and while we dressed the props we were never instructed which blade to have at the 12 o'clock position. Odd, maybe P-3s and C-13s had different pitch OK mechanisms? Whoever designed the stuff hat went inside that prop dome was a genius!

I think we have a couple P-3 FEs on here, maybe they'll chime in.

Fairly sure it was the same, at least our CP -140 guys (Canadian P-3s) dress props too.

[CF104]

I was wrong in my terminology but not my explanation, the #1 blade was up to prevent prop fluid from leaking from the housing.

You are correct, it is the beta feedback shaft. It's been 20 years since I worked Hercs, since then I have worked six different airframes (1 transport, four helo types, and 1 fighter).

I loved the Herc the most though.

Actually the vent in the beta feedback shaft(#1 blade) helped prevent static leaks of the blade root seals and dome seals as long as the #1 blade was dressed up. Fluid leakage from the pump housing was rare. The main purpose of the beta feedback vent was to drain any bypass of fluid from the pressurized dome back to the atmospheric sump of the pump housing. Otherwise you'd end up with massive blade root and dome base seal leaks.

I also spent 10 years on the Herk and it was my favorite aircraft to work on.

Cheers,

John

[SteveV22FE]

Yep! Kelly's right!

I remember as a young airman learning my CUT APG duties that the No.1 blade goes up! If I remember right there was a dot on the number one blade.

Steve E

C-130H GAC Troop

I have to disagree with an earlier post. The reason #1 blade is up is because of what is called the Beta Feedback shaft. It will leak prop fluid if it is in any other position. The Beta Feedback shaft tells the valve housing what angle the prop is at. (That is a VERY simplified way to explain it.) The pitchlock regulator is something that keeps a set of splines from engaging while pressure is on the dome assembly. The splines engaged will prevent the blade angle from decreasing to a flat or reverse position but will allow it to increase to a feather position if needed up to 92.5* blade angle to maintain a positive lock on the spline teeth.

If the prop looses pressure, the pitchlock regulator will dump pressure and the two spline gears will engage to keep the prop from doing what it wants. It will also pitchlock at 103.5% if the fuel control doesn't keep the engine below 103%. I flew 12 different C-130's in my 19 years of flying during my 24 years of Air Force service. Now, the 3-bladed props are electric and completely different than the Ham-Stan props and the J model props are completely different again. Can't compare those at all.

And here is a schematic of the pitch lock regulator.

I can get many more photos and graphics if anyone wants them but it really doesn't have much to do with model building other than the T-56 engine series -6 to -16 had the prop #1 blade at the 12 o'clock position. Right before engine start, the crew chief would break the prop break by X'ing the props. This helps the starter. The prop brake engages when prop oil pressure is above 23 psi. If the prop loses pressure, the prop brake engages and is held in place by a slight pressure on the blade to counter rotate due to blade shape. During Functional Check Flights, the prop would turn backwards all the time. We would slow down first. Then do the prop fails to feather checklist. If that didn't work, then bump a little blade angle on it to stop the spin. I could go on and on.....

MSgt (Ret.) Kelly Jamison

Former C-130 Evaluator/Instructor

317th Airlift Group, Dyess AFB, TX

Edited May 29, 2014 by SteveV22FE

[Kirk Taylor]

C-130 prop position quick reference guide:

Props ++0++ = plane is parked and not flying anytime soon.

Props xx0xx = plane ready to fly.

Props in any random position = plane just flown/run and either going up again soon or postflight not completed.

It's really that simple.

Kirk Taylor

Former C-130 Crew Chief

[Rob de Bie]

Gentlemen, with so much C-130 knowlegde in the house, I have to ask another propeller-related question!

As far as I know, the props of the C-130A, C-130E and C-130H moved forward with each engine update (T56A-9 in the A, T56A-7 in the E model, T56A-15 in the H model). A simple indicator is the prop warning stripe, that moved forward too. First it was on the sponson, then just ahead, then even a little more to the front.

With so many changes, no wonder that model manufacturers got confused. For example, the Italeri/Testors model has the short T56A-9 forward nacelle combined with the short T56A-7 rear nacelle, and the props are not all in one line.

Therefore I looked high and low to find accurate data, preferably in the shape of Fuselage Station numbers. So far I found the following only:

1. Unspecified model: props 29'1" (349") behind front end of radome

2. Unspecified model: front end of radome: FS 30.4

3. Together that would make FS 379.4 for the prop disc

4. C-130H: Front of nacelle / rear of spinner: FS 389.0, firewall: FS 485.5

Do you know of better station data of the front of the nacelle, or the prop discs? I would be very happy to crack this one finally..

Rob

[CF104]

Gentlemen, with so much C-130 knowlegde in the house, I have to ask another propeller-related question!

As far as I know, the props of the C-130A, C-130E and C-130H moved forward with each engine update (T56A-9 in the A, T56A-7 in the E model, T56A-15 in the H model). A simple indicator is the prop warning stripe, that moved forward too. First it was on the sponson, then just ahead, then even a little more to the front.

With so many changes, no wonder that model manufacturers got confused. For example, the Italeri/Testors model has the short T56A-9 forward nacelle combined with the short T56A-7 rear nacelle, and the props are not all in one line.

Therefore I looked high and low to find accurate data, preferably in the shape of Fuselage Station numbers. So far I found the following only:

1. Unspecified model: props 29'1" (349") behind front end of radome

2. Unspecified model: front end of radome: FS 30.4

3. Together that would make FS 379.4 for the prop disc

4. C-130H: Front of nacelle / rear of spinner: FS 389.0, firewall: FS 485.5

Do you know of better station data of the front of the nacelle, or the prop discs? I would be very happy to crack this one finally..

Rob

Hi Rob,

Most of my experience is on the E and H model. I have however worked on both the A and B model as well but only for a limited time.

The prop line for the B, E and H is exactly the same whether it has the T56-A-7 or the T56-A-15 for power. The QECU(nacelle) dimensions are the same and the aft face of the prop spinner afterbody is at FS 389 which places the prop disk at approx. FS 379.

The A model is a different beast altogether. The QECU's are quite a bit different from the B/E/H. I don't have any fuse station information handy for the A but I believe they were about 8-10 inches shorter than the B/E/H.

The differences you see with the prop stripe in relation to the MLG fairings has to do with the fairings and not the engine type on the B/E/H models. The B/E and early H models had the same forward MLG fairings which placed the prop stripe ahead of the fairings. With the changes on the H model from the GTC to the APU in the left fairing and replacing the cargo compartment A/C pack in the right fairing with a larger pack, the forward MLG fairings were made longer. This lengthening of the fairing placed the prop stripes on the fairings instead of ahead of them.

With the shorter QECU of the A model the prop stripes were just barely ahead of the MLG fairings.

Cheers,

John

[Rob de Bie]

Hi Rob,

Most of my experience is on the E and H model. I have however worked on both the A and B model as well but only for a limited time.

The prop line for the B, E and H is exactly the same whether it has the T56-A-7 or the T56-A-15 for power. The QECU(nacelle) dimensions are the same and the aft face of the prop spinner afterbody is at FS 389 which places the prop disk at approx. FS 379.

The A model is a different beast altogether. The QECU's are quite a bit different from the B/E/H. I don't have any fuse station information handy for the A but I believe they were about 8-10 inches shorter than the B/E/H.

The differences you see with the prop stripe in relation to the MLG fairings has to do with the fairings and not the engine type on the B/E/H models. The B/E and early H models had the same forward MLG fairings which placed the prop stripe ahead of the fairings. With the changes on the H model from the GTC to the APU in the left fairing and replacing the cargo compartment A/C pack in the right fairing with a larger pack, the forward MLG fairings were made longer. This lengthening of the fairing placed the prop stripes on the fairings instead of ahead of them.

With the shorter QECU of the A model the prop stripes were just barely ahead of the MLG fairings.

Hello John, thank you for taking the time to answer my nacelle question! Before replying, I tried to retrace the information that made me believe there were three nacelle lengths, and I think I misunderstood some information. Tonight I looked up the lengths of the -7 and -15 engines, and they are both 146 inches, the -9 is 145 inches. That would also support that the 130E and 130H nacelles are the same.

The prop warning stripe on the fuselage seems to move around slightly from airframe to airframe. It's especially visible on the 130A, where on some a/c it touches the (left) sponson, and on other it is slightly ahead. Maybe the painting instructions were not clear on that, so it's a bit risky to draw conclusions on the basis of the stripe. Thanks for pointing out that the sponson itself changed on the H model.

Rob

[Scooby]

Hello John, thank you for taking the time to answer my nacelle question! Before replying, I tried to retrace the information that made me believe there were three nacelle lengths, and I think I misunderstood some information. Tonight I looked up the lengths of the -7 and -15 engines, and they are both 146 inches, the -9 is 145 inches. That would also support that the 130E and 130H nacelles are the same.

The prop warning stripe on the fuselage seems to move around slightly from airframe to airframe. It's especially visible on the 130A, where on some a/c it touches the (left) sponson, and on other it is slightly ahead. Maybe the painting instructions were not clear on that, so it's a bit risky to draw conclusions on the basis of the stripe. Thanks for pointing out that the sponson itself changed on the H model.

Rob

The E&H QECs were definitely the same. I worked in engine bay on both E&H models. Until we wired them they could hang on either the E or H model.

[Rob de Bie]

The E&H QECs were definitely the same. I worked in engine bay on both E&H models. Until we wired them they could hang on either the E or H model.

Hello Scooby, thanks for the information! I'm going to check the Italeri and Airfix models tonight to see how they measure up.

Rob